In the Dutch Patent application No. 7,711,065, pen design features are mentioned whereby a slave ink reservoir is being used, as well as an ink injection system for the transport of ink from this reservoir to a master ink reservoir and an ink lock which prevents the build-up of a large accumulation of slave ink in the master ink reservoir.
The disadvantage of this pen design is that the ink lock cannot function effectively with an automatic or semiautomatic ink injection system to feed the master reservoir.